In telephone systems, electronic switches are used to route calls to their destination, e.g., as designated by a destination telephone number. They are also used to connect telephone service subscribers to various peripheral devices, such as, e.g., voice messaging systems (also sometimes referred to as voice mail systems), speech recognizers, voice dialing services, etc. Peripheral devices are usually provided with some degree of intelligence, e.g., logic in the form of a CPU, so that the subscriber and peripheral device can communicate in an interactive fashion and/or to enable the peripheral device to interact with the switch in a meaningful way. Peripheral devices with such built in intelligence are frequently referred to as intelligent peripherals or "IPs".
FIG. 1 illustrates a known telephone system 100 which supports voice mail services. The known system 100 includes first and second telephone networks 10, 11 coupled together by a fiber optic connection 32. Each of the telephone networks 10, 11 includes a plurality of telephones 12, 14, a central office (C.O.) switch 16 and first and second voice mail IPs 28, 30. As illustrated the switch 16 includes first and second interfaces 18, 24, a central processing unit (CPU) 20, memory 22 and digit receiver 26. As discussed below, the C.O. switch 16 is capable of connecting a telephone to a voice mail IP 28, 30 or one of the other telephones 12, 14. The central office switch 16 is coupled to each voice mail IP 28, 30 by a T1 link and a simplified message desk interface (SMDI) connection. The voice mail IPs 28, 30 can indicate to the central office switch 16 that a message is waiting for a particular subscriber and that the subscriber's message waiting light should be activated in the event that the particular subscriber's telephone 12, 14 includes message waiting light functionality.
One common technique for providing telephone service subscribers access to an IP, which provides a desired service, involves the subscriber dialing a telephone number corresponding to the IP. For example, when a subscriber to a voice mail service desires to check for received messages in one known system the subscriber would normally dial a telephone number corresponding to the subscriber's voice mail service. In response to detecting the telephone number corresponding to the voice mail IP, the C.O. switch 16 couples the voice mail subscriber to the voice mail IP 28 or 30 as indicated by the dialed telephone number. In addition to dialing the telephone number of the voice mail service, a subscriber may also have to enter into the telephone, e.g., by depressing a series of keys, account number and/or a personal identification number (PIN) required by the voice mail IP to gain access to the subscriber's account.
In the case of multi-party mail box accounts, once access to a voice mail account is obtained, the mail service may request that the subscriber depress one or more keys to identify which particular individual is attempting to retrieve his or her messages. For example, the caller may be asked to press "1" for John's messages or "2" for Mary's messages. Such mail systems may require a subscriber to enter, e.g., 10-20 keys, prior to the subscriber being informed as to whether or not there are any stored messages for the particular calling subscriber.
In addition to requiring a caller to enter account information, most voice mail systems may require the subscriber to press additional keys and thereby generate DTMF tones, e.g., to replay or delete a message.
The large number of keys which must be depressed, and thus the relatively large amount of time and effort required merely to discover whether a message is waiting for a subscriber, is a major disadvantage of the known mail system described above.
In order to facilitate the routing of calls to an IP, e.g., for providing voice mail and voice dialing services, a communication protocol referred to as the network facility access ("NFA") protocol, was designed for communicating information between a subscriber and an IP via a central office switch. This protocol overcomes the need for a subscriber to dial a telephone number to be connected to an IP when calling from the subscribers own telephone.
When the NFA protocol is enabled at the central office switch for a subscriber's telephone line, upon detecting an off-hook condition on the subscriber's line the central office switch will immediately establish a connection between the subscriber and an IP which is specified at the central office switch. In accordance with the NFA protocol, if the subscriber begins dialing a telephone number while the connection to the IP is being established, the central office switch will terminate the process of connecting the subscriber to the IP and route the call in the usual manner.
While use of the NFA protocol makes it easier for a subscriber to gain access to an IP by eliminating the need to dial a telephone number to be connected to the IP, there remains room for improvement in the manner in which subscribers are coupled to IPs and the manner in which IPs interact.
For the most part, subscribers to voice mail services usually want to be connected to a voice mail service when there is a new message waiting for them and not at other times. Accordingly, automatically coupling a subscriber to an IP which provides voice mail services in response to every off-hook condition of a subscriber can result in an inefficient use of switch and IP resources. This is because, in many if not most cases, the subscriber will be initiating the off-hook condition to place a call as opposed to connect to the voice messaging IP.
Problems may also arise with current methods of automatically connecting a telephone customer to an IP in response to an office hook condition when the telephone customer subscribes to multiple services implemented on different IPs. In the known systems, a subscriber is generally capable of being coupled automatically to a single IP in response to an off-hook condition.
Accordingly, if a telephone customer subscribes to multiple telephone messaging services, e.g., one for work and one for personal use, using known techniques he may only be able to be automatically connected to one of the services upon detection of an off-hook condition. This may force, for example, a person trying to retrieve business voice mail messages to dial a telephone number corresponding to a work voice mail service when at home and the home voice mail service when at work to check for messages.
Additional complications may arise in the known systems when, for example, when a subscriber to a voice messaging service also subscribes to a voice dialing service implemented on a different IP than the voice messaging service. In such a case, connecting a caller automatically to the voice dialing service IP in response to an off-hook condition may be preferable to connecting the caller to the voice messaging IP since the subscriber will, in many cases, place calls more frequently than check for messages. Unfortunately, automatically connecting the subscriber to one IP will normally preclude automatic connection to the other IP thereby preventing a subscriber from automatically having access to services provided on multiple IPs.
From the above discussion it is apparent that there is a need for improved methods and apparatus for connecting subscribers to peripheral devices. In particular, there is a need for methods and apparatus which enable a subscriber to be automatically coupled to a plurality of IPs in response to an off-hook condition.
In addition, there is a need for methods of improving the use of switch and IP resources by selectively connecting subscribers to IPs when the subscriber is most likely to use or desire access to the service provided by the IP and not in response to every off-hook condition initiated by the subscriber.
In addition to improving the efficiency and ease of the subscriber to IP connection process, it is desirable that the interaction with IP's be simplified from a subscriber's perspective. For example, it is desirable that the number of telephone keys a subscriber must press to obtain a desired service be minimized.
It is also desirable, from a cost and implementation efficiency standpoint, that circuitry found in one IP not be duplicated in other IPs which will service the same subscribers. It is also desirable from a cost and implementation standpoint that IP resources be used in an efficient and cost effective manner thereby minimizing overall IP and telephone system hardware costs.
In view of the above, it is apparent that there remains room for considerable improvement in how IPs are connected to subscribers, the way in which they are interconnected, and the actual manner in which IPs are implemented.